Sufficiency of disclosure stands as a foundational pillar within patent law



IIa Technologies Pte Ltd v Element Six Technologies Ltd [2023] SGCA 5



Court of Appeal






IIa Technologies Pte Ltd is a major manufacturer of CVD diamonds and has a diamond-growing facility in Singapore.



Element Six Technologies Ltd is a global leader in the design, development and production of synthetic diamond super materials.


Background of the Matter:

Element Six Tech Ltd and IIa Tech Pte Ltd are competitors in the production of synthetic diamonds grown using chemical vapour deposition (“CVD”). In 2016, Element Six filed suit against IIa, claiming infringement of two of its Singapore-registered patents, No. 115872 (“SG 872”) and 110508 (“SG 508”). In its defence, IIa filed a counterclaim disputing the validity of both patents and seeking their revocation.

The High Court revoked SG 508 for lacking novelty and inventive step. However, SG 872 was found to be valid and specific claims in that patent were found to be infringed by IIa.

IIa filed an appeal to challenge the Judge’s decision on validity and infringement, which is the subject of the present case.

Claim 1 and claim 62 of SG 872 were the pivotal claims in dispute. Claim 1 is directed to a CVD single crystal diamond material exhibiting at least one of eight quantifiable optical properties. One of these properties is characterised by the parameter δ and the values it may take. Claim 62 is directed to a method of growing the diamond material in the product claims and includes providing a synthesis atmosphere containing 300 ppb to 5 ppm nitrogen. IIa contended that both claims 1 and 62 did not fulfil the sufficiency requirement.



Whether the subject patent was invalid on grounds of insufficiency.



The Court of Appeal invalidated all claims of the subject patent on the basis of insufficiency, citing three key reasons:


The product claims were deemed classically insufficient as they failed to instruct the skilled person on how to grow diamonds across the entire range of products specified;


The process claims were similarly considered classically insufficient, as they imposed an excessive burden on the skilled person to determine the precise growth conditions necessary for the patented diamond-growing process.


In addition to the above, both the product and process claims were found insufficient due to uncertainty. The skilled person would have difficulty applying a specific test to determine if a particular diamond met the claimed parameter and satisfied the independent product claim.


Points of Interest:

There are two principles in relation to the legal requirement of sufficiency in Singapore. First, the burden of proving insufficiency rests on the party challenging the validity of a registered patent. Next, the assessment of sufficiency proceeds in two steps. The first step involves identifying the invention and deciding what it claims to enable the person skilled in the art to do. The second steps asks whether the specification enables him to do it.


The Court observed that knowledge dissemination means that the patent specification must disclose the invention in a clear and complete manner for it to be performed by a person skilled in the art.


A patent may be deemed insufficient in distinct ways. The most common way is “classical insufficiency”. This arises when the patent specification is not clear and complete enough to enable the person skilled in the art to perform the invention across the whole breadth of the claims without an undue burden.


Another way known as “Biogen insufficiency” arises when the patent claims more than what it teaches. Although this form of insufficiency is recognised in English law, the Court of Appeal did not address whether this is applicable under Singapore patent law.


The Court of Appeal has now accepted that insufficiency may also result from uncertainty, which arises where the skilled person is unable to determine whether a product or process falls within a claim.


There is a difference between uncertainty and the lack of clarity. The latter is not a ground for revocation. The test for clarity is whether the person skilled in the art can understand the words used in the claims.